This invention relates generally to a method and apparatus for attracting rodents by generating ultrasonic signals which correspond to the instinctual vocalization of rodents.
A number of attempts have been made to control the growth of the rodent population. Initially attempts were made to eliminate rodents by the use of mechanical traps including the conventional well-known mouse trap. While these traps have been successful, there are a number of drawbacks associated therewith including the fact that such traps are only capable of catching one rodent at a time and the rapid, forced movement of the mechanical trapping lever typically associated with such mouse traps present a danger to infants and domestic animals. In order to overcome the problems presented by conventional mechanical traps chemical poisons were developed for poisoning the rodents. Such rodenticides presented a serious problem in that the chemicals therein also affected domestic animals such as dogs and cats as well as human beings. Further, the use of such chemicals resulted in a delayed action on the rodents thereby resulting in the decaying carcasses of the poisoned rodents being left behind walls or in other inaccessible areas. Such decaying carcasses resulted in an offensive odor and attracted germs, flies and other undesirable insects to the surrounding area.
Because of the aforementioned problems, political entities have established programs for eliminating the food supply of the rodents. This depends upon uniform and consistent participation of everyone within the political entity. Such programs have failed in the past because of lack of full cooperation from everyone concerned.
More recently, attempts have been made to use ultrasonic devices for driving rodents away from an area. Such devices have proved to be ineffective since in the short term, the rodents merely went into another location with resulting damage to that location, and in the long run, the rodents returned. Attracting devices have been developed such as that disclosed in U.S. Pat. No. 3,414,873 for attracting fish. The device generates frequencies which correspond to the sound frequencies of a struggling fish for the purpose of attracting predatory fish thereto. This development makes use of the relatively low frequency sonar signals given off by the mechanical movement of a fish to attract predatory fish. Such a concept would hardly be likely to attract rodents and would, in fact, would be more likely to repel rodents for fear of danger to their own lives.
Moe disclosed in U.S. Pat. No. 3,328,908 an ultrasonic test control device for exterminating undesirable animals such as rodents. An ultrasonic signal having a deleterious effect on the nervous system of a rodent is generated so that the ultrasonic sounds envelope a given area. A series of shelters for the animals are provided within the area enveloped by the ultrasonic sound waves which shelters constitute traps for the animals. Such an arrangement, if it is not to be used simply as a repellant requires the provision of shelters readily accessible to the rodents, and positioned such that the rodents will seek refuge therein rather than simply running away from the ultrasonic sound source. Other devices for repelling undesirable fish is disclosed in Thomas et al, U.S. Pat. Nos. 3,524,276 and for repelling insects in White, 3,891,962. None of the devices disclosed in these patents provide a device which will result in the substantial elimination of undesirable animals from a given locality.
Accordingly, it is an object of this invention to provide a method and apparatus for attracting undesirable animals to a pre-selected location by generating ultrasonic signals corresponding to the instinctual vocalization of such animals.